Electrolytic cell



June 22, 1954 c B JR 2,681,887

ELECTROLYTIC CELL Filed Feb. 5, 195

3 Sheets-Sheet 1 FIG. 3 FIG. 2

INVENTOR. CLARENCE A. BUTLER,JR4

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June 22, 1954 c; BUTLER, JR 2,681,887

ELECTROLYTIC CELL Filed Feb. 3, 1950 3 Sheets-Sheet 2 cLARENc E A. BUTLER, JR.

3 Sheets-Sheet 3 FIG. l0

ELECTROLYTIC CELL c. A. BUTLER, JR

FIG. 9

INVENTOR. CLARENCE A. BUTLER, JR.

FIG- 8 Patented June 22, 1954 UNITED STATES PATENT OFFICE ELECTROLYTIC CELL Clarence A. Butler, Jr., Painesville, Ohio, assignor to Diamond Alkali Company, Cleveland, Ohio, a corporation of Delaware Application February 3, 1950, Serial No. 142,267

13 Claims. 1

This invention relates to electrolytic cells for the electrolysis of aqueous solutions of electrolytes. It more particularly is concerned with cells for the electrolysis of alkali metal chloride solutions to produce the corresponding alkali metal hydroxide and chlorine and has especially to do with cells which are capable of producing such products without concomitant production of hydrogen. This is a continuation-in-part of my co-pending application Ser. No. 578,303, filed February 16, 1945, now abandoned.

Various methods have heretofore been proposed to reduce the cost of operation of electrolytic cells, especially those for the production of alkali metal hydroxide, such as caustic soda, and chlorine, by reducing the amount of electrical energy necessary to operation of such cells. The energy requirements are, in general, the sum of the potential necessary to discharge chlorine at the anode, overcome polarization of the anode, overcome the resistance of the electrolyte, overcome polarization at the cathode, and discharge hydrogen at the cathode. Especially since hydrogen is a by-product of the electrochemical reactions involved, and. is considered to be of less value than the basic products of chlorine and, in the case of sodium chloride electrolysis, caustic soda, it has been appreciated for some time that if the main products of the reactions involved could be obtained without the production of hydrogen, a considerable saving could be eifected.

It has heretofore been proposed to reduce the polarization of the cathode in alkali-chlorine cells by introducing oxygen into a porous cathode, but these means have been limited by the fact that polarization is not completely eliminated, and more particularly, that in any case hydrogen must be discharged at the cathode and the consequent potential for that purpose be available across the cell. However, a cell adapted for practical commercial design which avoids polarization of the cathode by avoiding production of hydrogen at the cathode has not heretofore been proposed, even though the need for such a cell has been appreciated by workers in the art.

It is an object of the present invention to provide an electrolytic cell particularly for the electrolysis of aqueous solutions of electrolytes having a cathode comprising a porous, oxygen-activating, oxygen-containing, electrolyte-solutionrepellent member having an electrically active face, the cell also including a diaphragm between the anode and the cathode, and electrically inert spacers between said diaphragm and said electrically active face of said cathode.

It is a further object of the invention to provide such a cell in which said spacers comprise flow 2 elements and provide channels for the withdrawal of the catholyte from the cell.

It is a further object of the invention to provide such a cell in which said catholyte withdrawing elements serve to withdraw said catholyte while in contact with the electrolytically active face of the cathode.

A further object of the present invention is to provide an electrolytic cell for the production of chlorine and caustic soda without the accompanying production of hydrogen and with consequent savings in the cost of the main products of the electrolysis reaction.

As is known in the art, cells in which chlorine and caustic soda are produced generally operate at a voltage of 3 to 3.5 volts or more and have a theoretical or open circuit voltage, i. e., voltage drop across the cell when no current is flowing therethrough, of about 2.3 volts. Such cells, in addition to production of caustic soda and chlorine, produce large amounts of hydrogen gas, which of course is a dangerous material to handle and which must be disposed of in some manner avoiding such danger. In some cases such hydrogen gas, which may be produced in amounts as much as 10,000 cubic feet per ton of chlorine, has been put to use in various manufacturing processes but, in general, such processes cannot be satisfactorily integrated with a chlorine-caustic operation and hence, the hydrogen by-product represents a nuisance to the electrolytic cell operator.

In contrast to prior art procedures, the present invention contemplates the production of alkali metal hydroxides, such as caustic soda, and chlorine electrolytically without the accompanying production of hydrogen. With the cell of the present invention, savings in electrical potential as high as 30% have been achieved. Thus, it is possible to operate the electrolytic cell of this invention to produce chlorine and caustic soda at a potential of about 1.9 to 2.4 volts, as contrasted with the potential noted above of 3 to 3.5 volts of the prior art hydrogen-producing cells. The corresponding open circuit potential of the present cell is 1.6 volts or less, in contrast with the above-noted open circuit potential of 2.3 of the prior art.

The structure of the present invention is par ticularly concerned with provision of means to permit the gravity flow of the catholyte in contact with the active face of the cathode downwardly and out of electrolytic contact with the cathode. As noted above, the cathode itself preferably comprises an oxygen-activating material, suitably being of a substance capable of adsorbing oxygen and rendering it available in electro chemically active form. In general, for this purpose cathodes comprising activated carbon are preferred, which carbon may be in the form of a solid block or matrix or which may be in granular form and held in position in the cell by metal screening or the like. In the case of .a block of activated carbon, suitable porosity is provided to permit the passage of gases through the block of material by means known in the art not forming a part of this invention.

In accordance with the present invention, the" cathode is suitably of non-wettable,. electrolytesolution-repellent material, thisendlbeing obtained by rendering the carbonaceous matter of the cathode electrolyte-solution-repellent by various known means, such as pre-treating the cathode material with a carbon tetrachloride solution of parafiin, or benzene solution of rubber, or the like. Such treatment, followed by suitable drying to remove the solvent, renders the carbon of the cathode suitably solutionrepellent so that the same is substantially unwetted by the electrolyte solution, and in accordance with the present invention, penetration of the catholyte into the body of the oathode thus may suitably be avoided.

Moreover, in accordance with the present invention, oxygen-containing gases, which may be oxygen itself, air, or other suitable mixtures having appreciable oxygen content, are suitably supplied to the cathode whereby the oxygen is activated in the cathode by the oxygen-activating carbon. In accordance with a particularly preferred feature of the present invention, provision is made for blowing oxygencontaining gases into the cathode, which is suitably provided with paths of egress for such gases, which paths of egress do not include the electrically active face of the cathode.

While the equations for the reactions occurring in the cell of the present invention have not been established beyond peradventure, considerable evidence exists for the following theory of operation of such a cell, which theory is especially persuasive since it accounts for the experimentally observed reduction in potential necessary to operate the cell. Thus, in a conventional chlorine-caustic cell employing a conventional anode, cathode, and diaphragm therebetween, the electrochemical reaction at the cathode may be represented as follows:

It is seen that hydrogen ions, whether hydrated or not, indication of hydration being omitted for simplicity, are produced at the cathode where two electrons there available, join with the hydrogen to produce gaseous hydrogen in the form of H2, which is evolved at the cathode and which, of course, causes the polarizing difficulties mentioned above. In contrast to this prior art method, the method of the present invention, which provides electrochemically activated oxygen at the cathode, combines this oxygen with water and the electrons available at the cathode in accordance with the following equation:

That this is the apparent cathode reaction is evidenced not only by the absence of the production of any hydrogen whatsoever at the oathode and the reduction in potential noted above, but also by experimentally observed high concentration of hydroxyl ions in the neighborhood of the cathode, which hydroxyl ions cannot be accounted for in any other manner than by the above equation.

The formation of hydroxyl ions at the cathode in this manner insures that sodium ions migrating to the cathode and. which would in a conventional cell become sodium atoms, react with water and thus produce hydrogen, will rather react with the hydroxyl ions without any hydrogen formation.

For a more complete understanding of the cell of the present invention, reference is made to the following description including the drawings, in which Fig. 1 is a top plan view of a cell embodying the method of the present invention;

Fig. 2 is a section taken on line 2-2 of Fig. 1, looking in the direction of the arrows;

Fig. 3 is a section on line 33 of Fig. 1, looking in the direction of the arrows;

Fig. 4 is a section on line 4-4 of Fig. 2, looking in the direction of the arrows;

Fig. 5 is a perspective view of a means for making electrical connection to the cathode;

Fig. 6 is a perspective view, with parts broken .away for clarity, of the entire cell;

Fig. 7 is a section similar to Fig. 4 of a modified form of the cell;

Fig. 8 is a side elevation with parts broken away and parts. in section, showing a modified form of the invention comprising an arrangement for a battery of cells;

Fig. 9 is a top plan view of .a portion of the structure of Fig. 8; and

Fig. 10 is a section .taken on the line I0-I0 of Fig. 9.

Referring particularly to Figs. 1-6, the cell as shown comprises anode assembly A and cathode assembly B, which are held in assembled position by clamping means shown generally at C.

The anode assembly A includes the casing or box-like member I, which has an open side as may be seen from Figs. 2 and 6. The box member I is provided at its upper end with a feeder and separator chamber 2 communicating with the anode chamber interior through opening passages 3 and having a liquid inlet pipe 4 and a gas outlet 5. Box or anode container I may suitably be fashioned of a material which .is not afiected by the liquid or gaseous prodnets to which it is exposed and is further preferably electrolytically non-conductive and impermeable to the gaseous and liquid products of electrolysis. As shown, concrete is a suitable material for this purpose.

Anode 6 may suitably be a rectangular block of carbon or the like of such dimensions to permit its being positioned, as particularly shown in Figs. 2 and 3, within the box I and out of contact with the interior surfaces of said box and with suihcient space between the anode 6 and the walls of the box to permit the accommodation of an adequate quantity of electrolyte solution. Anode 6 may be supported in box I by any suitable means, such as conductors "I and conductor sheath 8, which extend from outside of box I, where they may be attached to a suitable source of potential (not shown), into and through the walls of box I and, as particularly shown in Fig. 3, into the anode 6. The sheathing 8 may suitably be of some sealing material to prevent the escape of electrolyte solution from the box I and may, moreover, be of electrically insulating material, whereby the conductors I are protected from the electrolyte solution. A suitable material for this purpose is any asphaltic sealing material. The recessesin the anode into which the conductors I extend may suitably be lined with conductive material 9, such as antimony-lead, or the like, in order to insure good electrical contact between. the anode and the conductors I.

The cathode assembly B, as shown in Figs. 1-6, comprises, referring particularly to Fig, 6, electrolyte-solution-permeable diaphragm I0, asbestos cords I cathode II, and conductor I2. As shown in Fig. 6 and also in Fig. 4, diaphragm It may suitably be slightly larger in area than the open space at the back of box i, whereby this space is completely covered by the diaphragm in the course of assembling the cell. The diaphragm may comprise any suitable material, such as asbestos paper or the like, which material is preferably inert to the electrolyte solution and products of electrolysis.

Situated behind diaphragm In and mounted in parallel vertical relationship are a plurality of spacers or flow elements comprising asbestos cords I l, preferably comprising long fibered asbestos threading oriented along the longitudinal axis of the cords, which cords have the function with respect to diaphragm ill of support thereof and which cords also act as spacers to provide a physical spacing between the diaphragm In and the actual cathode I l. The cords I4 may suitably extend from the top of the diaphragm, which itself is suitably co-extensive from the top of the cathode II, to a point below the lower extremity of both the diaphragm and the cathode H, as particularly shown in Fig. 2. While the spaces between cords I4 provide means for escape of liquids coming through the diaphragm, the cords themselves comprise downwardly directed capillary channels or passageways for liquids passing through the diaphragm. Moreover, the cords assure that the liquid which come through the diaphragm bridges the gap between the diaphragm I I] and cathode I I and comes into electrochemical contact therewith. The diaphragm itself, however, will be observed particularly in Fig. 6 to be held entirely out of physical contact with the cathode II by the discontinuous spacer means. Accordingly, the hydrostatic head of the solution in the cell does not bear directly against the active face of the cathode, whereby seepage of such solution into the oxygen filled cathode is avoided. A particular advantage of this arrangement therefore is that the waterproofing of the carbon of the cathode need not be of highest efiiciency, even in a large cell as in any case, hydrostatic head against the cathode is precluded. Cathode I I may suitably be a single block-like matrix of gas-permeable activated carbon which has been rendered repellent to the electrolyte solution, whereby it is not wetted by the solution. The inner face of cathode II bears, as noted above, against the cords I4 which space it from the diaphragm Ill, and the outer face of the oathode i in electrical contact with conductor I2, which is more particularly illustrated in Fig. 5. As shown in Fig. 5, conductor I2 may suitably resemble an inverted F, in which both of the arms I 5 in the F are provided with windows I 6.

Clamping assembly C comprises solid rectangular supports 23, 2|, which may suitably be held in place as by bolts 22. The bolting serves to secure or clamp the cathode assembly firmly against the open side of box I and thus maintains the parts in assembled position. Any suitably rigid material of adequate strength and electrical neutrality may be employed for the supports 20, 2 I, examples of such materials being wood, either natural or plywood, and various plastic materials.

Piping assembly I3 suitably extends through support El and terminates in the windows I6 of conductor I2, whereby oxygen-containing gases may be blown through pipe I3 into contact with cathode I I. Moreover, as noted above, the oathode II is of porous material, i. e., porous carbon, so that it is possible to pump air or oxygen-containing gases through pipe I3 and into cathode I I. However, as may be observed especially from Fig. 2, suitable passages through the porous carbon are provided in all cases, shorter than the passage from the entrance point of gases into the cathode I I to the active electrode face in contact with the cords I l. By this means, the passage of gases through the porous carbon cathode is assured and equally assured is the removal of the gases either from the periphery of the cathode II or other portions thereof not including the electrically active face, so that no oxygen-com taining gases are blown into the area of electrical activity.

Caustic soda formed in the course of the electrolysis passes through the diaphragm II) and flows downwardly largely through the cords I4 and is collected in trough 23 and may be drawn from the cell through collecting pipe 24.

The modification shown in Fig. 'I will be recognized as substantially the same cell as Figs. 1-6, differing only in the construction of the cathode. Thus, in this embodiment of the present invention, the cathode comprises a quantity of finelydivided electrolyte-solution-repellent activated carbon 25 held in place juxtaposed to the cords I 4 and diaphragm Ill by frame 21, which may suitably comprise metallic screen or the like. The extension 29 of the screen may be employed for the purpose of securing or attaching the screen to a source of potential. The screen may suitably present a flat surface to the electrolytically active portion of the cell and as shown, may have the irregular surface 26 at the rear thereof, whereby the space between the support 2I and the irregular surface of the screen provides a zone for introduction of oxygencontaining gas through pipe 28 or the like.

Screen 26 is so designed to permit the oxygencontaining gas either as delivered by pipe 28 or entering from the atmosphere to permeate the granular carbon material 25 and to escape from the cathode, without passing into the electrolyte, through the screen 25 at the portions not exposed to gas introducing means, thus preventing the passage of gases through the diaphragm or past the electrolytically active face of the cathode.

As inferred in the paragraph above, the use of subsidiary means, such as piping I3 in Figs. 1-6, and piping 28 in Fig. 7, to introduce oxygenoontaining gas into the cathode may be dispensed with, especially in the case of operation of a single or a small number of cells. Particularly, however, in large batteries of cells where a considerable quantity of oxygen is required and insuihcient oxygen may be present in the atmosphere fully to supply the needs of the cathodes and present sufficient oxygen to the electrolytically active face of the cathode in electrochemically active form, piping l3 and 28', plus introduction of oxygen-containing gases, is preferred.

In Figs. 8-10 is shown a form of the invention especially adapted to commercial operations. Thus, these figures illustrate cells of the present invention mounted in series to form a battery of head, which may be integral.

of in the electrolytic chamber proper. lfilling the cell,and if means for introducing adaccuse? cells, wherein considerable economies of construction and'operation' may be efiectedby multiple use of parts. In these figures, except as otherwise indicated, the parts of the cell are identical with the cell of Figs. 1-6, and it will be understood that the same principles of multiple construction and operation apply to other embodiments of the invention, including that of Fig.7. Thus, the cell unit includes base Gil and prises a chamber comparable to chamber 2 of Figs. l-G-and is similarly equipped with brine inlet Mandchlorine outlet 45 and having passages48 to the main body of the cell which has anode 5|], which may be mounted as before.

Closing the cell on both sides is diaphragm 52, supported by cords 54, behind which is cathode '56, all of which are mounted in the same relation to'each other. as in Figs. 1-6. Conductor 58 is similar to conductor l2, except that, as shown in Fig..10, the ends of the bifurcated arms of the F are. open for a reason to be stated below.

Each conductor 58 is shared by two juxtaposed cathodes of adjacent cell units of a battery. Brine may suitably be supplied to the cells of a battery through lines shown diagrammatically at 69 as collected in brine header 62, and chlorine may leave the cells through lines 64 into header E6. Troughs 68, which collect caustic solution from cells, similarly may lead to collector 70.

'While, as noted in connection with Figs. 1-6,

theair-filled cathodes of this invention may operate without the introduction of oxygen-containing gases thereinto, it is especially preferred in the form of the invention shown in Figs. 8--l0,

that provision be made for such supplemental oxygen introduction, since in view of the large number of cells which may be crowded into a restricted space, oxygen deficiency might result were such precaution omitted. Thus, referring particularly to Fig. 10, conductor 58 is provided with bus 12 for attachment to a suitable source of potential (not shown) and has divided arms 14a, 1), and 16a, b, and as shown especially in Fig. 8, is suitably interposed between the outsides v or non-electrochemically active faces of two cathodes. Introduction of oxygen-containing gases is suitably efiected through conduits T5, 80, which lead respectively to the spaces between the arms 14a and b and 16a and b. Headers 82,

84 connect to conduits 18, 3D and are fed from any convenient source indicated at 86.

A battery of cells of any convenient size may thus be assembled and held in place by end supports 88, 9%, which may suitably be bolted as at 92, 94 or otherwise secured.

The structure of this embodiment has not only the advantages and savings which arise from quantity operation but also has the useful feature that only parts of complete cells are necessary to build up the assembly. Moreover, the saving in floor space, and thus in building investment, over prior art systems of batteries of individual cells is substantial.

The operation of the cells is substantially selfapparent in view of the description above but, referring, for example to the cell of Figs. 1-6, in-

'cludes the introduction of electrolyte, such as sodium chloride solution, into the chamber 2 through inlet 4 until the liquid level stands above opening 3 and preferably until the chamber 2 is substantially more than half full, whereby some additional brine is present to allow for use there- Upon Head 42 com- 51 ditional air or otheroxygen-containing gas to the cathode are to be employed, the air is turned on in contact with the cathode as, for example, illustrated in Fig. 2, and passes through the porous electrolyte-solution-repellent cathode and escapes therefrom without crossing the electrolytically active face of the cathode. Thereupon, the electric circuit may be closed and as the electrolysis proceeds, chlorine is collected in chamber 2 and drawn off through outlet pipe 5 and catholyte runs down the cords l4 and therebetween and drips off the bottom of the cords, the cords being, as noted above, specifically provided as slightly longer than the elements with which they are in contact, electrolysis continuing while the solution is continuing downwardly in the cords M by virtue of electrolytic contact with the electrolytically active face of the cathode containing oxygen in electrochemically active form. The catholyte dripping off the bottom of the cords I4 is collected in trough 23 and may be withdrawn from the cell through pipe 24.

Electrolyte may be replenished as needed through the inlet 4 in chamber 2, the electrolyte preferably being added at a temperature of above C. in order to maintain the temperature in the cell between about and C. Such addition of further electrolyte may, of course, be automatically adjusted to the needs of the cell and will normally not require the attention of an operator.

In accordance with the present invention and as may be observed from the exemplary cells illustrated in the drawings, the oir or oxygenfilled cathode is not under any hydrostatic pressure whatsoever during the operation of the cell. The seepage through the diaphragm l8, referring, for example, to Fig. 6, is picked up by the cords t which draw the liquid by capillary action downwardly and out and away from the cell. This flowing liquid, however, is in electrolytic contact with the active face of the cathode but no hydrostatic pressure exists thereagainst. Moreover, the pressure of air or oxygen-containing gas in the cathode obviously is not relied upon to withhold the seepage of solution into the cathode both for the reasons pointed out above and for the reason that the cell is suitably designed to permit the passage of the oxygencontaining gas through the cathode and out of the cathode at some point other than the electrolytically active face thereof. This is suitably accomplished by providing paths of least resistance which do not include this active face.

While there have been described various embodiments of the invention, the apparatus described is not intended to be understood as limiting the scope of the invention as it is realized that changes therewithin are possible and it is further intended that each element recited in any of the following claims is to be understood as referring to all equivalent elements for accomplishing substantially the same or equivalent manner, it being intended to cover the invention broadly in Whatever form its principle may be utilized.

What is claimed is:

1. An electrolytic cell for the electrolysis of aqueous solutions of electrolytes including a container for the electrolyte, one of the vertical containing walls thereof being formed by a permeable diaphragm, an anode within the container, a cathode outside the container in juxtaposition to the diaphragm, and means to pass electric current between said anode and said cathode, said cathode including a porous, oxygenactivating, water-repellent conductor of electricity, and a discontinuous non-electrolytically active solution-wettable spacer between said cathode and said diaphragm, said spacer comprising vertically running, laterally spaced, asbestos cords which extend below the lower edge of both the diaphragm and the porous member.

2. An electrolytic cell for electrolysis of aqueous electrolytes including a container for the electrolyte, an anode within said container, a cathode outside said container, and means to pass electric current therebetween and through said solution, a permeable diaphragm forming a portion of said container for the electrolyte and interposed between said anode and said cathode, said cathode including a porous, oxygen-activating, water-repellent conductor of electricity and a plurality of individual non-electrolytically active solution-wettable spacers mounted between said diaphragm and said water-repellent conductor, said spacers being spaced from each other, each being mounted to contact both the diaphragm and the conductor and form a discontinuous bridge for liquid passing through said diaphragm to contact said conductor in current passing relation.

3. A cell as claimed in claim 2, wherein said spacers form the main support for said diaphragm.

4. A cell as claimed in claim 2 including means to supply oxygen to said water-repellent conductor and in which said water-repellent conductor has paths of least resistance for passage of oxygen therethrough, which paths terminate in portions thereof which are maintained out of contact with said solution-wettable spacers.

5. A cell as claimed in claim 2, in which said conductor comprises a block of porous, waterrepellent, active carbon.

6. A cell as claimed in claim 2, in which said conductor comprises a foraminous container substantially filled with granular, porous, waterrepellent, activated carbon.

7. An electrolytic cell for electrolysis of aqueous solutions of electrolytes including a container for the electrolyte, an anode within said container, a cathode outside said container, a diaphragm between said anode and said cathode forming a portion of said container for the electrolyte, and means to pass electric current between said anode and said cathode, said cathode including a vertically disposed porous, oxygenactivating, water-repellent conductor of electricity, individual solution-wettable spacer drainage means mounted between said diaphragm and said water-repellent conductor in spaced relation from each other and extending below the bottom edge of said conductor and said diaphragm, and forrning a discontinuous bridge for liquid passing through said diaphragm to contact said conductor in current passing relation, said spacer drainage means being in contact with said diaphragm and said cathode and mounted to drain solution coming through said diaphragm downwardly and out of the cell while said solution is in contact with said cathode, and means to collect the solu tion drained through said spacer drainage means.

8. An electrolytic cell for the electrolysis of aqueous solutions of electrolytes including means to contain electrolyte, an anode contained within said means, a cathode situated outside said means, and means to pass electric current between said anode and said cathode, said cathode including a porous, oxygen-activating, water-repellent conductor of electricity, a diaphragm between said cathode and said anode and individual discontinuous non-electrolytically active solution-wettable spacer means between and in contact with said cathode and said diaphragm, comprising vertically arranged, laterally spaced members of substantially similar thickness and of discontinuous web form mounted for flow of liquid therethrough by capillarity.

9. A cell as claimed in claim 8, wherein said spacer comprises vertically arranged, laterally spaced, asbestos cords.

10. A cell as claimed in claim 8, wherein said Spacer comprises vertically arranged, laterally spaced, asbestos cords of long fiber asbestos.

11. A cell for the electrolysis of aqueous solutions of electrolytes including a container having an open side, an anode positioned in said container and out of contact with the inner surfaces thereof, a permeable diaphragm covering the open side of said container, solution-wettable channel forming cord means mounted in vertical relation, spaced one from another, on the outside of said diaphragm and comprising the main support for said diaphragm, and adapted to form drain passages for solution passing through said diaphragm, a porous, oxygen-activating, waterrepellent electrical conductor in contact with said spacer means, and means to supply oxygen to said conductor.

12. A multiple electrolytic cell for electrolysis of electrolyte solutions including a series of open sided containers mounted to face each other on their open sides, an anode in each of said containers mounted out of contact with the inner surfaces thereof, a permeable diaphragm covering each of the open sides of each container, a plurality of individual solution-wettable, nonelectrolytically active spacers mounted outside said diaphlragms, each of said spacers being spaced from each other but mounted to contact said diaphragms; one of said containers, an asso ciated pair of said diaphragms and spacers for said diaphragms comprising an anode assembly; cathodes including porous, oxygen-activating, water-repellent conductors of electricity, mount ed to contact said spacers on either side of anode assembly, said conductors being mounted to provide passage for potential applied to the cell, common electrolyte solution header means for introduction of electrolyte to each of the anode assemblies, withdrawal means for products of electrolysis joined to common outlets, means to supply potential to said cell and means to supply oxygen-containing gases to two conduc tors serving opposite sides of a juxtaposed pair of anode assemblies.

13. A cell as claimed in claim 12, wherein said means to supply potential to said cell includes a series of individual busses, each being mounted to supply potential from a source thereof to two adjacent conductors serving opposite sides of a juxtaposed pair of anode assemblies.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 596,157 Hargreaves Dec. 28, 1897 652,611 Hargreaves June 26, 1909 697,157 McDonald Apr. 8, 1902 1,097,826 Townsend May 26, 1914 2,011,171 Baker Aug. 13, 1935 2,273,795 Heise et al Feb. 17, 1942 2,358,419 Schumacher Sept. 19, 1944 2,390,591 Janes Dec. 11, 1945 

1. AN ELECTROLYTIC CELL FOR THE ELECTROLYSIS OF AQUEOUS SOLUTIONS OF ELECTROLYTES INCLUDING A CONTAINER FOR THE ELECTROLYTE, ONE OF THE VERTICAL CONTAINING WALLS THEREOF BEING FORMED BY A PERMEABLE DIAPHRAGM, AN ANODE WITHIN THE CONTAINER, A CATHODE OUTSIDE THE CONTAINER IN JUXTAPOSITION TO THE DIAPHRAGM, AND MEANS TO PASS ELECTRIC CURRENT BETWEEN SAID ANODE AND SAID CATHODE, SAID CATHODE INCLUDING A POROUS, OXYGENACTIVATING, WATER-REPELLENT CONDUCTOR OF ELECTRICITY, AND A DISCONTINUOUS NON-ELECTROLYTICALLY ACTIVE SOLUTION-WETTABLE SPACER BETWEEN SAID CATHODE AND SAID DIAPHRAGM, SAID SPACER COMPRISING VERTICALLY RUNNING, LATERALLY SPACED, ASBESTOS CORDS WHICH EXTEND BELOW THE LOWER EDGE OF BOTH THE DIAPHRAGM AND THE POROUS MEMBER. 